1. Field of the Invention
The present invention relates to a so-called projector-type vehicular headlamp, and, in particular, to a vehicular headlamp including a liquid crystal shutter.
2. Related Art
In projector-type vehicular headlamps, in general, a projection lens is disposed on an optical axis extending in a vehicular longitudinal direction, a light source is disposed rearwardly of a rear-side focal point of the projection lens, and a reflector reflects light from the light source toward the projection lens. In order for a projector-type vehicular headlamp to form a low-beam distribution pattern, a shade that blocks a part of reflected light from the reflector is disposed in the proximity of the rear-side focal point of the projection lens with the upper end edge of the shade positioned in the proximity of the optical axis, so as to form a cut-off line at the upper end edge of the low-beam distribution pattern.
“Patent Document 1” describes a vehicular headlamp in which the above shade is movable to selectively form a low-beam distribution pattern and a high-beam distribution pattern.
Meanwhile, “Patent Document 2” and “Patent Document 3” describe a vehicular headlamp in which a liquid crystal shutter is disposed in place of the above shade in the proximity of the rear-side focal point of a projection lens. In the vehicular headlamp described in each of “Patent Document 2” and “Patent Document 3,” a part of an area of the liquid crystal shutter can be driven to selectively form a low-beam distribution pattern and a high-beam distribution pattern.
[Patent Document 1] Japanese Patent Application Laid-Open (Kokai) No. JP-A-2007-80521
[Patent Document 2] Japanese Patent Application Laid-Open (Kokai) No. JP-A-H1-244934
[Patent Document 3] Japanese Patent Application Laid-Open (Kokai) No. JP-A-H7-296605